Disable Right Click Selection Change

[John]

By default the tree view will change selection by clicking on a item with left or right mouse, I need to prevent the selected item from changing when a item is clicked with the right mouse, instead i need to hilight the item and pop a context menu.
Also where do you change the color of the selected background?
Thanks

[Ivan Petrov]

Hi John,

Thank you for writing.

You can cancel the selection with right mouse button in the RadTreeView SelectedNodeChanging event using the following code:

void radTreeView1_SelectedNodeChanging(object sender, RadTreeViewCancelEventArgs e)
{
  if (Control.MouseButtons == MouseButtons.Right)
  {
    e.Cancel = true;
  }
}

In the MouseDown event you can highlight the node you click and show your context menu. Here is a code snippet on how to do that:

void radTreeView1_MouseDown(object sender, MouseEventArgs e)
{
  if (e.Button == MouseButtons.Right)
  {
    RadElement element = this.radTreeView1.ElementTree.GetElementAtPoint(e.Location);
    if (!(element is TreeNodeElement))
    {
      element = element.FindAncestor<TreeNodeElement>();
    }

    if (element  as TreeNodeElement != null)
    {
      ((TreeNodeElement)element).DrawFill = true;
      ((TreeNodeElement)element).BackColor = Color.Red;
    }
  }
}

void radTreeView1_NodeFormatting(object sender, TreeNodeFormattingEventArgs e)
{
  e.NodeElement.ResetValue(LightVisualElement.DrawFillProperty, ValueResetFlags.Local);
  e.NodeElement.ResetValue(LightVisualElement.BackColorProperty, ValueResetFlags.Local);
}

You need the code in the ItemFormatting event to remove the highlighting of the item.

I hope this will be useful for you. If you need further assistance, I would be glad to help. All the best,
Ivan Petrov
the Telerik team

[Marcus]

I did solve this in a different way:

Private m_lstSelectedNodes As New List(Of RadTreeNode)

Private Sub rtvTest_SelectedNodeChanged(sender As Object, e As Telerik.WinControls.UI.RadTreeViewEventArgs) Handles rtvTask.SelectedNodeChanged

 

    If Control.MouseButtons <> Windows.Forms.MouseButtons.Left Then

        For Each rtvnNode As RadTreeNode In m_lstSelectedNodes

            rtvnNode.Selected = True

        Next

 

        m_lstSelectedNodes.Clear()

    End If

 

End Sub

 

Private Sub rtvTest_SelectedNodeChanging(sender As Object, e As Telerik.WinControls.UI.RadTreeViewCancelEventArgs) Handles rtvTest.SelectedNodeChanging 

    If Control.MouseButtons = Windows.Forms.MouseButtons.Right Then

        m_lstSelectedNodes.Clear()

        For Each rtvnNode As RadTreeNode In rtvTask.SelectedNodes

            m_lstSelectedNodes.Add(rtvnNode)

        Next

 

        e.Cancel = True

    End If

End Sub

[Ivan Petrov]

Hi Marcus,

Thank you for sharing your solution.

The solution you have came up with is perfectly legal with only one minor draw back - the memory you need for the selected nodes collection you have to keep and the triggering of the selection events again. When you set the Selected property of a node, you trigger all the events that follow a selection, involving the events in which you trigger it.

I hope this will be useful for you. Should you need further assistance, feel free to write back.

Best wishes,
Ivan Petrov
the Telerik team